# Sugar restriction in the first 1000 days after conception, and long-term respiratory health: a quasi-experiment study

## TL;DR

Restricting sugar intake during the first 1000 days after conception may reduce adult asthma and COPD risks and improve lung function.

## Contribution

This study provides novel evidence linking early-life sugar restriction to long-term respiratory health benefits using a quasi-experimental design.

## Key findings

- Early-life sugar restriction was associated with a 25% lower risk of asthma and 27% lower risk of COPD in adulthood.
- Sugar-restricted individuals had improved lung function metrics, including higher FEV1%, FVC%, and FEV1/FVC ratios.
- Diabetes and hypertension partially mediated the protective effects of sugar restriction.

## Abstract

High sugar intake during the first 1000 d after conception is common and may impact lifelong respiratory health. Although early-life sugar exposure has been linked to childhood asthma, its long-term effect on adult respiratory disease and lung function is unclear.

This study aims to assess whether restricted sugar intake during the first 1000 d after conception is associated with risk and delayed onset of asthma, chronic obstructive pulmonary disease (COPD), and idiopathic pulmonary fibrosis (IPF) in adulthood, and to explore potential mediating mechanisms.

We used the cessation of the United Kingdom’s sugar rationing in September 1953 as a quasi-experiment, comparing 58,670 UK Biobank participants born 1951–1956 exposed to varying durations of early-life sugar restriction. Participants were classified as exposed (in utero and/or ≤2 y postbirth) or unexposed (born after July 1954). Outcomes included incident asthma, COPD, and IPF (ascertained by health records), validated in the English Longitudinal Study of Ageing (a United Kingdom cohort) and the Health and Retirement Study (a United States cohort). Spirometry indices [forced expiratory volume in 1 s (FEV1)%, forced vital capacity (FVC)%, FEV1/FVC] were measured. Cox models adjusted for demographic, socioeconomic, lifestyle, and clinical factors. Mediation analysis assessed diabetes, hypertension, and birth weight.

Early-life exposure to sugar rationing (in utero plus 1–2 y) was associated with lower risks of asthma [hazard ratio: 0.75; 95% confidence interval (CI): 0.61, 0.91] and COPD [0.73 (0.62, 0.88)], and delayed disease onset by ≤3.6 y. Rationed participants had higher mean FEV1% (increase 6.0; 95% CI: 2.9, 9.1), FVC% [increase 5.9 (3.3, 8.5)], and FEV1/FVC ratio [increase 0.045 (0.011, 0.079)] compared with nonrationed groups. Longer sugar restriction offered greater protection. Diabetes and hypertension mediated 18.2% of the effect; birth weight contributed only 1.6%. Findings were consistent across external validation and placebo analyses.

Restricting sugar intake during the first 1,000 d after conception was associated with reduced risk and delayed onset of asthma and COPD, and improved lung function in adulthood. These findings support the utility of current dietary guidelines to promote lifelong respiratory health.